Continued efforts will be directed toward the synthesis of other metabolites of the hydrocarbon benzo(a)pyrene. A wide range of radiochemically labeled arene oxides will be prepared for use as substrates in the study of epoxide hydrase and glutathione-5-epoxide transferase, as well as for binding studies to cellular components. New arene oxides of benzo(a)pyrene will be synthesized. Homogeneous epoxide hydrase will be prepared and its mechanism of action examined. Metabolism of polycyclic aromatic hydrocarbons by bacteria will be further elucidated. Both in vivo and in vitro studies of the biological activity of synthetic benzo(a)pyrene metabolites will be described in the next report.